Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C263/00—Preparation of derivatives of isocyanic acid
  • C07C263/18—Separation; Purification; Stabilisation; Use of additives
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
  • C08G18/72—Polyisocyanates or polyisothiocyanates
  • C08G18/721—Two or more polyisocyanates not provided for in one single group C08G18/73 - C08G18/80
  • C08G18/727—Two or more polyisocyanates not provided for in one single group C08G18/73 - C08G18/80 comprising distillation residues or non-distilled raw phosgenation products
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
  • C08G18/72—Polyisocyanates or polyisothiocyanates
  • C08G18/74—Polyisocyanates or polyisothiocyanates cyclic
  • C08G18/76—Polyisocyanates or polyisothiocyanates cyclic aromatic
  • C08G18/7614—Polyisocyanates or polyisothiocyanates cyclic aromatic containing only one aromatic ring
  • C08G18/7621—Polyisocyanates or polyisothiocyanates cyclic aromatic containing only one aromatic ring being toluene diisocyanate including isomer mixtures

Definitions

• This invention relates to a process for the preparation of commercially valuable polyisocyanate compositions and, more particularly, to the corrrelative preparation of an isomeric tolylene diisocyanate mixture and a particular crude tolylene diamine phosgenation product.
• a mixture of 80% 2,4-tolylene diisocyanate and 20% 2,6-tolylene diisocyanate and a tolylene diamine phosgenation product comprising a tolylene diisocyanate solution of congeneric non-volatile polyisocyanate solutes, the tolylene diisocyanate solution having an amine equivalent between about 90 and about 125, are commercially wellknown products finding utility in the polyurethane field.
• the former i.e., the mixture of 80% 2,4-tolylene diisocyanate and 20% 2,6-tolylene diisocyanate
• Nacconate 80 which is described by Rose in the Condensed Chemical Dictionary, 6th edition, Reinhold Publishing Corp., 1961, at page 773.
• the latter i.e., the tolylene diamine phosgenation product, is sold commercially as Nacconate 4040, which is referred to by Ferrigno in Rigid Plastic Foams, Reinhold Publishing Corp., 1963, at pages to 10.
• Tolylene diamine phosgenation products having an amine equivalent between about 98 and about 120 are exemplified and disclosed in the copending application of Melvin Kaplan, Ser. No. 225,873, filed Sept. 24, 1962, now US. Patent 3,215,652, wherein tolylene diamine phosgenation products are prepared by reacting a mixture of 80% 2,4-tolylene diamine and 20% 2,6-tolylene diamine with phosgene in the presence of a solvent and then distilling solvent and tolylene diisocyanate from the re action mixture until the distilland is composed of a tolylene phosgenation product comprising a tolylene diisocyanate solution of congeneric non-volatile polyisocyanate solutes, said solution having an amine equivalent between 3,426,058 Patented Feb.
• the distilland as noted above, is commercially valuable.
• the distillate was found to be a mixture of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate in such undesirable proportions that the 2,4-tolylene diisocyanate was less than 78% by weight of the mixture.
• the distillate could be subjected to elaborate refining procedures or the addition of pure and expensive 2,4-toly1- ene diisocyanate to the mixture, if available.
• An object of'this invention is to provide a process for th correlative preparation of two commercially desirable materials, i.e., a mixture of 80% 2,4-tolylene diisocyanate and 20% 2,6-tolylene diisocyanate and a tolylene diamine phosgenation product comprising a tolylene diisocyanate solution of congeneric non-volatile polyisocyanate solutes, said solution having an amine equivalent between about and about 125, especially between 98 and 120.
• the symbol 1 is defined as plus or minus two percent by weight which is sufiicient tolerance for the commercial product of the mixture of 80% by weight 2,4-tolylene diisocyanate and 20% by weight 2,6-tolylene diisocyanate. In other words a ratio of 78% to about 82% by weight of 2,4-tolylene diisocyanate to 18% to 22% 2,6-tolylene diisocyanate provides a satisfactory mixture for the uses to which this mixture is to be subjected in the polyurethane art.
• all 80/ 20 isomeric mixtures of diisocyanates or diamines referred to herein are i values, i.e., these values are considered to cover the range of two percent by weight on the positive or negative side of the value, such values being by weight.
• the Kaplan application referred to, supra, discloses a tolylene diamine phosgenation product comprising a tolylene diisocyanate solution of congeneric non-volatile polyisocyanate solutes, said solution having an amine equivalent between about 98 and about 120, and preferably between about 102 and about 108.
• This tolylene process comprising the following steps:
• the practice of the art was to take the distillate of this process, which is a mixture of less than 78% by weight 2,4-tolylene diisocyanate with greater than 22% by weight 2,6-tolylene diisocyanate and add either pure and expensive 2,4-tolylene diisocyanate or carry out elaborate refining procedures to get the commercially desirable 80/20 ratio.
• the distillate By returning a portion of the distillate, which can be in the range of about 20% to about 60% by weight of the distilland to the distilland until the amine equivalent of the distilland reaches between about 98 and about 120, two commercially valuable products are made available.
• the distillation step of the present invention can be carried out according to conventional distillation techniques and the step is preferably carried out under vacuum. Standard equipment is satisfactory.
• the process of the present invention is preferably conducted in a continuous manner as follows:
• an inert solvent such as dichlorobenzene
• the distillate is stripped of solvent and divided into two streams, one of which is transferred to a product column for final processing and the other fed into another storage tank.
• the contents of the two storage tanks, i.e., the distilland and the distillate are then blended until the amine equivalent of the distilland is between about 98 and about 120.
• Isocyanate equivalent weight or amine equivalen Isocyanate equivalent weights are measured by an analytical procedure which involves reacting the isocyanate groups in the sample with n-dibutyl amine to form the corresponding urea groups and back titrating excess n-butylamine with HCl solution.
• the procedure is as follows: weight 6 to 8 grams of sample, dilute with 35 to 50 cc. of toluene, add 20 cc. of a 2 N solution of dibutylamine in toluene, heat to minutes (do not boil), cool, add 100 cc.
• the distilland in the evaporator is withdrawn into a first storage tank.
• the tolylene diisocyanate isomeric mixture is withdrawn from the column at a rate of about 1195 pounds per hour until it is composed of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate in an average ratio of 79.5 parts to 20.5 parts and is divided into two effiuent streams: one of the streams is for final processing of the tolylene diisocyanate product containing 2,4-tolylene diisocyanate and 2,6- tolylene diisocyanate in the above-mentioned ratio; the second stream is fed into a second storage tank.
• the contents of the two storage tanks are blended in the ratio of 2 parts of distilland to 1 part of distillate yielding a tolylene diamine phosgenation product suitable for the manufacture of urethane polymers having an amine equivalent of 107 and an average viscosity of 50 to 60 centipoises.
• a process for the correlative preparation of a mixture of about 80- :2% by weight of 2,4-tolylene diisocyanate and about 20i2% by weight of 2,6-tolylene diisocyanate and a tolylene diamine phosgenation product comprising a tolylene diisocyanate solution of congeneric non-volatile polyisocyanate solutes, said solution having an amine equivalent between about and about 125, comprising the steps:
• a process for the correlative preparation of a mixture of 80:2% by weight 2,4-tolylene diisocyanate and about 20i2% by weight of 2,6-tolylene diisocyanate and a tolylene diamine phosgenation product comprising a tolylene diisocyanate solution of congeneric non-volatile polyisocyanate solutes, said solution having an amine equivalent between about 98 and about 120 comprising the steps: (a) distilling a tolylene diamine phosgenation product prepared by the phosgenation of a mixture of 801-2% by weight of 2,4-tolylene diamine and 20:':2% by weight of 2,6-t0lylene diamine, said phosgenation product comprising a tolylene diisocyanate solution of congeneric non-volatile polyisocyanate solutes, until a distillate, which is at least 50% by weight of the initial phosgenation product, becomes a mixture of about 80i2% by weight of 2,4

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Polyurethanes Or Polyureas (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=23733245

Family Applications (1)

Country Status (4)

Cited By (2)

Citations (1)

• 1965
  • 1965-03-02 US US436647A patent/US3426058A/en not_active Expired - Lifetime
• 1966
  • 1966-03-01 GB GB8978/66A patent/GB1063609A/en not_active Expired
  • 1966-03-01 BE BE677219D patent/BE677219A/xx unknown
  • 1966-03-01 DE DE19661543987 patent/DE1543987A1/de active Pending

Patent Citations (1)

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